Last night, I connected megatron's BO board to the analog dewhitening board.  However, I was unable to lock the y arm (although once I disconnected the cable and reconnected it back the xy220 the yarm did lock).

So either A) I've got the wrong cable, or B) I've got the wrong logic being sent to the analog dewhitening filters.

During testing, I ran into an odd continuous on/off cycle on one of the side filer modules (on megatron).  Turns out I had forgotten to use a ground input to the control filer bank (which allows you to both set switches as well as read them out), and it was reading a random variable.  Grounding it in the model fixed the problem (after re-making).